Foam suppressor for soluble oils



Patented Feb. 4, 1941 UNITED STATE n 2,230,556 1 n FOAM surrmassoa FOR SOLUBLE on.s

.John 0. zimmer, Hillside, and George M. McNulty, Union, N. J., assignors to Standard Oil Development Company, a corporation of Delaware No Drawing. Application January 11, 1938, Serial No. 184,382

I 6 Claims.

This invention relates to mineral oil emulsions, especially those used for metal working, and is more particularly. concerned with agents toprevent or retard the foaming thereof.

Mineral oil emulsions are used in metal workingsuch as the cutting and .grinding of. gears,

tools, crank-shafts, ball bearings, pistons, etc.

These emulsions ordinarily consist of a mineral oil, an emulsifyingagent and water. l

The mineral, oil may be a light lubricating fraction of petroleum, a spindle oil, white oil or similar type of oil. Distillate oils derived from paraflinic ornaphthenic crudes and having Saybolt viscosities at 100 F. between 60 and 200 secondsare generally suitable. The emulsifying agent may be a sodium, potassium or onium base naphthenate orsulfonate. Organic naphthenate soaps such as diand triethanolamine naphthenate may also be used. It is generally preferable to use a mixture of naphthenates and sulfonateasay in a ratio of 1 part naphthenate to 4 parts sulfonates. The .naphthenates are found to cause excessive foaming and are also more water soluble than the sulfonates. From 5 to 40% by weight of the emulsifying agent based on the mineral oil may be used.

It is found that these mineral oil emulsions when agitated and stirred up as they must be in metal working generate considerable foam which is not only'troublesome to work with but also causes overflow of the reservoirs and tanks from which the emulsion is supplied.

Several methods for preventing foaming of mineral oil emulsions have been'proposed heretofore. The usual method is to prepare a comparatively unstable product, thus producing emulsions which separate free oil. This free 011 acts to some extent as a foam suppressor. The principal disadvantage of this method, however, is that unstable emulsions tend to separate completely under prolonged service.

Another method is to add aluminum stearate or stearic acid to the soluble oil. These materials are not especially satisfactory because the soda present either as free alkali or formed by hydrolysis of sodium sulfonate or naphthenate soaps tends to displace the aluminum or react with the stearic acid to form sodium stearate. This sodium stearate tends to cause gelling or solidification of the soluble oil which, of course, is highly objectionable.

The present invention is directed to a new method for suppressing the foaming tendency of .soluble oils. The nature of this method will be fully understood from the following description We have found that waxes of acids having more than 22 carbon atoms and containing from 5 to 50% of free acid having at least 22 carbon atoms have the property of suppressing or substantially preventing the foaming of soluble oil emulsions. The most suitable wax of this type is montan wax, but other waxy derivatives of montan wax such as waxes known as OP and Ziflwaxes manufactured and sold by the I. G. Farbenindustrie A. G. of Germany are also suitable. These waxes are added to the soluble'oil in amounts between '.001% and about 0.5% by weight. The amount of wax added in any particular case should not, of course, be sumcient to cause separation of the wax from the oil at normal temperatures. It is preferable to heat the soluble oil to about the melting point of the wax and then stir it in vigorously. Overheating of the oil should be avoided.

These waxes are especially effective in suppressing foam formation in. cases where the emulsifying agent is a naphthenate soap.

It will be understood that other materials may also be added to the soluble oils besides these foam suppressors. For example, dyes, anti-oxidants, polymer thickeners, resins or, in fact, any of the usual addition agents for hydrocarbon oils may be added without interfering with the action of the waxes. I

To illustrate the method, a, SOhlblQOil containing a mixture of sulfonate and naphthenate soaps as an emulsifying agent is mixed with 40 parts of water to form an emulsion. To another portion of soluble oil about 0.01% montan wax is added and emulsified with 40 parts water. The two emulsions are tested for foaming using a Mixmaster agitator.

The following results are obtained:

M ixmaster foaming test 700 R. P. M. for minutes. 500 cc. sample.

. gfi g Time for foam volume to break Percent 1 Emulsion 160 20 minutes. 2 Emulsion +0.01% montan wax 0 l-2 seconds In another experiment various quantities of wax identified as OP wax manufactured by the I. G. Farbenindustrie A. G. were added to the soluble oil containing naphthenate soap. These samples were tested in the Mixmaster as above and the following results obtained:

These results show that as little as 0.01% of montan wax and as little as 0.02% of "OP" we. will markedly reduce the foaming tendency of the soluble oil when emulsified.

Following are formulae for typical soluble oils prepared in accordance with the present invention:

mineral ester wax of an acid having at least 22 carbon atoms in amount sufficient to reduce the foaming tendency of said 011.

2. Composition of matter comprising a mineral oil, a small percent of an emulsifying agent selected from the class consisting of alkali naphthenates, alkali sulfonates and mixtures of alkali naphthenates and alkali sulfonates, said Per cent\'' emulsifying agent being present in sufilclent Sodium sulfonate 12.00 Naphthenic acids 3.00 Sodium hydroxide 0.50 Alcohol 0.50 Water 2.00 Montan wax 0.05 Paraffin 81.95

Per cent Sodium sulfonate 12.00 Rosin 4.60 7 Sodium hydroxide 0.50 Alcohol 0.50 Water 2.00

Montan wax 0.05 Parafiin nil 80.35

This invention is not limited by any theories of the mechanism of the foaming nor by any details which have been given merely for purposes of illustration, but is limited only in and by the following claims in which it is intended to claim all novelty inherent in the invention.

We claim:

1. Composition of matter comprising a mineral soluble oil containing a small per cent of an emulsifying agent selected from the class consisting of alkali naphthenates, alkali sulfonates, and "mixtures of alkali naphthenates and alkali sulfonates and having the property of producing a substantial amount of foam under service conditions and a small percent of a amount to produce a stable emulsion but also to cause substantial amounts of foam, and a small percent of an ester wax of an acid having at least 22 carbon atoms containing at least of free acid having at least'22 carbon atoms in amount sufllcient substantially to reduce foam formation.

3. Composition of matter comprising a mineral oil, a small percent of an emulsifying agent selected from the class consisting of alkali naphthenates, alkali sulfonates and mixtures of alkali naphthenates and alkali sulfonates, and a small percent of montan wax in amount sufllcient substantially to reduce foam formation.

4. Composition of matter comprising a mineral oil, a small percent of an alkali naphthenate and between 0.001 and 0.5% by weight of montan wax.

5. A non-foaming emulsion comprising water, a mineral oil, a small percent of an alkali naphthenate, and between 0.001 and 0.5% of montan wax.

6. A non-foaming emulsion comprising water, a mineral oil, from 5 to 40% by weight of an emulsifying agent selected from the class consisting of alkali naphthenates, alkali sulfonates, and mixtures of alkali naphthenates and alkali sulfonates, and between 0.001 and 0.05% montan wax.

JOHN C. ZIMIWER. GEORGE M. MCNULTY. 

